|Publication number||US7362849 B2|
|Application number||US 11/325,023|
|Publication date||Apr 22, 2008|
|Filing date||Jan 4, 2006|
|Priority date||Jan 4, 2006|
|Also published as||US20070152159|
|Publication number||11325023, 325023, US 7362849 B2, US 7362849B2, US-B2-7362849, US7362849 B2, US7362849B2|
|Inventors||Jonathan Short, Martin Lee, J. Eric Tkaczyk, David Hoffman, Brian David Yanoff|
|Original Assignee||General Electric Company|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (13), Referenced by (9), Classifications (10), Legal Events (3)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention relates generally to a detector system, and, more particularly to a two dimensional (2D) collimator assembly which may be employed in a detector system.
Computed tomography (CT) is utilized for a wide variety of imaging applications, such as medical imaging. CT systems are imaging systems that are generally configured to transmit x-rays through a structure, such as a human body, to detect and diagnose abnormalities, such as tumors. These low energy x-rays are subsequently received and processed to formulate an image, often three-dimensional, of the body structure that can by analyzed by clinicians as a diagnostic aid.
The reception of the radiation, such as gamma rays or x-rays, is often accomplished through the use of a device such as a detector assembly. The detector assembly is typically comprised of a plurality of structures working together to receive and process the incoming energy rays after they have passed through the body structure. The detector assembly utilizes a scintillator assembly to convert incident radiation, such as x-rays, into light for detection at an array of light detection devices. Scintillation allows the radiation received by the scintillator assembly to be converted into useful information. Scintillator assemblies may come in a wide variety of forms and may be adapted to receive a wide variety of incoming rays. The light produced by the scintillator assembly is commonly received (or “detected”) and processed by a detection device such as a light sensitive photodiode, which converts the light from the scintillator assembly into an electronic signal. The information from the scintillator assembly can be easily transferred, converted, and processed by electronic modules in a data acquisition system to facilitate viewing and manipulation by clinicians.
Typically, detector assemblies also include a collimator assembly. A collimator assembly is typically designed to reduce x-ray scatter and/or shield the underlying elements from undesirable exposure. The collimator assembly is used to reduce x-ray scatter as the x-rays approach the scintillator element. Scattered photons can cause excess noise and artifacts in the reconstructed CT images. In addition, the collimator is commonly used as a shielding device for shielding the edges of the individual scintillator cells and to prevent x-rays from impinging on the edges of the scintillators causing non linearities and image artifacts. The collimator may also be employed to prevent x-rays from damaging the reflector between scintillator elements, to prevent x-rays from being transmitted through the gap between scintillator elements and impinging on the photo diode causing noise and/or to prevent x-rays from being transmitted through the gap between scintillator elements and impinging on electronics located behind the detector causing damage to these sensitive electronic components. Thus, present collimator assembly designs commonly attempt to balance shielding and scatter reducing properties.
Currently, CT collimator assemblies are 1-dimensional (1D) arrays assembled from long, thin metal blades, such as tungsten blades. In conventional systems these blades are >75 mm long, 200 um thick, and 7-8 mm tall. Approximately 1000 of these blades are assembled onto a precisely machined support rail to create a complete collimator assembly. While useful for scatter reduction and shielding, typical 1D collimator assemblies have a number of disadvantages. The assembly process is often tedious, and the cost of assembly is a significant fraction of the total cost of the collimator. In addition, at high gantry rotation rates, the tungsten blades deflect and cast shadows onto part of each detector pixel, causing gain-error artifacts in the image. Further, current collimator assembly designs are not easily extended to wider detectors (more slices) because of the mechanical stability of the blades. As desired detection areas grow, this shortcoming becomes an increasingly significant obstacle. Still further, the total amount of scatter impinging on the collimator increases roughly in proportion to the z-coverage of the detector. At the coverage that will soon be desired, the ability of the 1D collimator to reject the incoming scatter becomes increasingly inadequate.
Therefore, there is currently a need for a collimator assembly that provides for wider scanning areas, improved structural durability and simpler fabrication techniques.
In accordance with exemplary embodiments of the present invention, there is provided a collimator assembly. The collimator assembly comprises a plurality of blades arranged in parallel with respect to one another, wherein each of the plurality of blades comprises a body and a respective plurality of fins coupled to the blade and extending therefrom, and wherein each of the respective plurality of fins is coupled to an adjacent one of the plurality of blades.
In accordance with further exemplary embodiments of the present invention, there is provided a collimator assembly comprising a first blade and a second blade. The first blade has a first plurality of fins extending therefrom. The second blade is arranged in parallel to the first blade and having a second plurality of fins extending therefrom.
In accordance with another exemplary embodiment of the present invention, there is provided an imaging detector assembly. The imaging detector assembly comprises a detector array. The imaging detector array further comprises a scintillator assembly configured to receive incident radiation and configured to convert the incident radiation to light for transmission to the detector array. The imaging detector array further comprises a collimator assembly comprising a plurality of blades arranged in parallel with respect to one another, wherein each of the plurality of blades comprises a respective plurality of fins coupled to the blade and extending therefrom, and wherein each of the respective plurality of fins is coupled to an adjacent one of the plurality of blades.
In accordance with still another exemplary embodiment of the present invention, there is provided a method of fabricating a collimator assembly. The method comprises forming a plurality of blades, wherein each of the plurality of blades comprises a respective plurality of fins extending therefrom, and coupling each of the respective plurality of fins to an adjacent one of the plurality of blades.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Referring now to
The CT imaging system 10 includes a scanner assembly 12 illustrated as a gantry assembly. The scanner assembly 12 includes an x-ray source 14 for projecting a beam of x-rays 16 toward the detector assembly 18 positioned opposite the x-ray source 14. The detector assembly 18 includes a plurality of detector elements arranged to form a detector array 20, which is configured to sense the projected x-rays 16 that pass through an object, such as a medical patient 22. As will be appreciated, the patient 22 is typically said to be positioned along the Z-axis. Each of the plurality of detector elements in the detector array 20 produces an electrical signal that represents the intensity of an impinging x-ray beam and hence the attenuation of the beam 16 as it passes through the patient 22. Commonly, during a scan to acquire x-ray projection data, the scanner assembly 12 is rotated about the center of rotation 24. In one embodiment, illustrated in
The rotation of the scanner assembly 12 and the operation of the x-ray source 14 are preferably governed by a control mechanism 26. The control mechanism 26 preferably includes an x-ray controller 28 that provides power and timing signals to the x-ray source 14 and a scanner motor controller 30 that controls the rotational speed and position of the scanner assembly 12. A data acquisition system (DAS) 32 in control mechanism 26 samples analog data from the detector array 20, commonly a photodetector array, and converts the data to digital signals for subsequent processing. An image reconstructor 34 receives sampled and digitized x-ray data from DAS 32 and performs high speed image reconstruction. The reconstructed image is applied as an input to a computer 36 which stores the image in a mass storage device 38.
The computer 36 may also receive commands and scanning parameters from an operator via an operator console 40 that has a keyboard or similar input device. An associated display 42 allows the operator to observe the reconstructed image and other data from the computer 36. The operator supplied commands and parameters are used by computer 36 to provide control signals and information to the DAS 32, x-ray controller 28, and scanner motor controller 30. In addition, the computer 36 operates a table motor controller 44 which controls a motorized table 46 to position the patient 22 within the scanner assembly 12. Particularly, the table 46 moves portions of the patient 22 through the scanner opening 48.
Referring now to
Advantageously, the 2D collimator assembly 50 illustrated in
Referring now to
In one exemplary embodiment, the blade 54 and the fins 56 and 58 comprise a solid piece material. That is, the blade 54 is fabricated as a solid piece having fins 56 and 58 extending therefrom. For instance, the blade 54 having fins 56 and 58 extending therefrom in one solid piece may be formed by employing a molding process, for example. Alternatively, the center portion of the blade 54 may be fabricated as a single piece and each of the fins 56 and 58 may be later attached thereto using a glue or epoxy, for example. The fins 56 and 58 may comprise the same material as the body of the blade 54. Alternatively, the fins 56 and 58 may comprise a different material than the body of the blade 54. In one exemplary embodiment, the fins 56 and 58 comprise a polymer material loaded with a high atomic number material, such as tungsten power, for instance.
Referring now to
It should be noted that while
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
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|U.S. Classification||378/154, 378/7, 378/149|
|Cooperative Classification||G01T1/1648, G01T1/1642, G21K1/025|
|European Classification||G01T1/164B1, G01T1/164B9, G21K1/02B|
|Jan 4, 2006||AS||Assignment|
Owner name: GENERAL ELECTRIC COMPANY, NEW YORK
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SHORT, JONATHAN;LEE, MARTIN;TKACZYK, J. ERIC;AND OTHERS;REEL/FRAME:017445/0264;SIGNING DATES FROM 20051219 TO 20051222
|Sep 23, 2011||FPAY||Fee payment|
Year of fee payment: 4
|Oct 22, 2015||FPAY||Fee payment|
Year of fee payment: 8